Computer storage devices
Definition of computer storage devices
A storage device is any type of computing hardware that is used for storing, porting or extracting data files and objects. Storage devices can hold and store information both temporarily and permanently. They may be internal or external to a computer, server or computing device. (Techopedia, 2020)
The usage of storage devices
1. Storage devices are used for saving images in camera.
2. Storage devices are used in computers for store data for processing.
3. Storage devices are use in CCTV system for store captured videos
4. Storage devices are use in Entertainment system for store songs and videos
5. Storage devices are use in Servers for store websites data.
6. Storage devices are use in microcontrollers for store programs.
Types of storage
Primary storage
A primary storage device is any storage device or component that can store nonvolatile data in computers, servers, and other computing devices. It is used to hold/store data and applications temporarily or for a shorter period while the computer is running. Primary storage is also known as main storage, main memory, or internal memory. (Techopedia, Primary Storage Device, 2013)
Examples:
1. Random Access Memory (RAM)
Random access memory allows CPU to read as well as write data and instructions into it. RAM is much faster to read from and write to than hard disk or floppy disk. The major limitation of this type of memory is that it is volatile — when power is turned off, the contents of the primary memory are lost forever. There are two types of RAM.
2. Read Only Memory (ROM)
ROM is the memory from which we can only read but cannot write on. This type of memory is non-volatile and stores instructions that are required to start a computer. ROM chips are also used in other electronic items like washing machines and microwave ovens for example.
Examples:
Masked ROM
Programmable ROM
Erasable Programmable ROM
Electrically Erasable Programmable ROM
Flash ROM
3. Cache Memory
Cache memory is an extremely fast memory type that acts as a buffer between RAM and the CPU. It holds frequently requested data and instructions so that they are immediately available to the CPU when needed. Cache memory is costlier than main memory or disk memory but economical than CPU registers.
There are three levels have cache memory.
1. Level 1
2. Level 2
3. Level 3
· Secondary storage
Secondary storage devices primarily refer to storage devices that serve as an addition to the computer’s primary storage, RAM, and cache memory. These devices store virtually all programs and applications stored on a computer, including the operating system, device drivers, applications, and general user data. Typically, secondary storage allows for the storage of data ranging from a few megabytes to petabytes.
They are used for a variety of purposes ranging from backup data used for future restores or disaster recovery, long-term archiving of data that is not frequently accessed, and storage of non-critical data in lower-performing, less expensive drives. The fundamental characteristics of secondary storage are high capacity and low cost, although speed, reliability and portability might also be important. For example, a lot of data from the previous decades that has been stored on magnetic tapes is now practically unusable.
Most of the secondary storage devices used to be internal to the computer such as the hard disk drive, the tape disk drive and even the optical storage drive (CD-ROM, Blu-ray, and DVD) and floppy disk drive. For example, many organizations store their archival data or critical documents on secondary storage drives which cannot be accessed by their main network to ensure their preservation whenever a data breach occurs. However, today, many secondary storage drives are frequently external, especially since the introduction of USB flash drives and plug-and-play devices. Also, many secondary storage devices are now virtual devices residing on third-party cloud servers hosted by many services.
· Tertiary storage
It involves a robotic mechanism which will mount and dismount removable mass storage media into a storage device according to the system’s demands. When a computer needs to read information from the tertiary storage, it will first consult a catalog database to determine which tape or disc contains the information. Next, the computer will instruct a robotic arm to fetch the medium and place it in a drive. When the computer has finished reading the information, the robotic arm will return the medium to its place in the library. (STORAGE TECHNOLOGIES BY: SHIVENDRA GAURAV, n.d.)
Examples of Tertiary storage
1. Magnetic Tapes
2. Optical Discs
3. Optical tapes
· Offline storage
offline storage is any storage that is not currently online, live or connected to the computer. The data stored in offline storage remains permanently in the storage device even if it’s disconnected or unplugged from the computer after the data has been stored. Offline storage is generally portable in nature and can be used on different computer systems. Common examples of offline storage include floppy disks, compact disks, and USB sticks. (Techopedia, Offline Storage, 2013)
Types of computer storage devices
· Magnetic storage devices
Magnetic storage is also known as “Magnetic Media” or “Magnetic Memory” or “Magnetic Medium “. In the Magnetic storage devices, all data are stored with using magnetized medium, and those types of data saved in that medium in the binary form like as 0 and 1. This magnetic storage has also non-volatile storage nature. Today’s, mostly people are preferred to magnetic medium because on the magnetic storage devices can be performed read/write activities very easily. Magnetic storage devices have huge capacities for storing data that it’s more attractive point. (E.R S, 2021)
· Optical Devices
Optical storage provides greater memory capacity than magnetic storage because laser beams can be controlled and focused much more precisely than can tiny magnetic heads, thereby enabling the condensation of data into a much smaller space. In optical-storage technology, a laser beam encodes digital data onto an optical, or laser, disk in the form of tiny pits arranged in a spiral track on the disk’s surface. This technology is used in the compact disc, which records sound; in the CD-ROM (compact disc read-only memory), which can store text and images as well as sound; in WORM (write-once read-many), a type of disk that can be written on once and read any number of times; and in newer disks that are totally rewritable. The data on them cannot be destroyed by power outages or magnetic disturbances, the disks themselves are relatively impervious to physical damage, and unlike magnetic disks and tapes, they need not be kept in tightly sealed containers to protect them from contaminants. Despite its slowness, its superior capacity and recording characteristics make optical storage ideally suited to memory-intensive applications, especially those that incorporate still or animated graphics, sound, and large quantities of text.
electronic storage medium that uses low-power laser beams to record and retrieve digital (binary) data. The chief remaining drawback to optical equipment is a slower rate of information retrieval compared with conventional magnetic-storage media. Early optical disks were not erasable — i.e., data encoded onto their surfaces could be read but not erased or rewritten.
· Flash Memory devices
Flash memory technology is visible in many forms: everything from the familiar Flash USB memory sticks and camera memory cards like Compact Flash cards or CF cards and SD memory cards, right through to applications as computer solid-state hard drives where it is replacing the older disc technologies which are slower, less reliable, and more fragile. With its widespread usage, Flash has become one of the more widely used forms of semiconductor memory, and with its use extending from the widely seen memory sticks and camera memory cards etc. into items like solid-state hard drives for computers, the technology is being seen even more. Flash memory is a non-volatile form of electronic data storage and as a result, it is used in many areas where short and medium-term data storage is needed. (E., n.d.)
· Online Cloud storage devices
In the software industry, cloud means a service that runs on the internet and stores your data at a “remote location,” which means the data center of a cloud service provider. The main objective of the cloud, instead of saving data at local storage, the data of the user can be collected at some data center so the user could retrieve his or her data from any device. In cloud storage, the data that you have stored at your device or hard drive can be stored at the data center of the cloud service provider. Cloud storage works on a client-server model, in which a client sends the request to the subscribed cloud service storage and the server at the data center gives the appropriate response. The cloud storage depends on hundreds of data centers, so even if one of the data centers collapses, there are hundreds of centers that would help you to retrieve and save your data. What if the data center of the cloud service provider collapses or gets destroyed, would the user data also be destroyed? The cloud service storage works as a bank that stores your data so you can access it from anywhere and any device. (V., 2020)
Examples: — Google Drive, Flickr, Microsoft Sky Drive
Most used storage devices
o Hard disk
Hard disk drives are non-volatile magnetic disk devices capable of remembering vast amounts of data. An electromagnet in the read/write head charges the disk’s surface with either a positive or negative charge, this is how binary 1 or 0 is represented. The read/write head is then capable of detecting the magnetic charges left on the disk’s surface, this is how data is read. The disk surface is divided into concentric circles (tracks) and sectors (wedges). Dividing the surface in this way provides physical addresses to remember where data is saved. A circuit board carefully co-ordinates the rotating disk and swinging actuator arm to allow the read/write head to access any location very quickly. Typical HDD capacities are measured in Terabytes (TB). They can be installed inside a computer or purchased in a portable (external) format. (Storage Devices, 2019)
o Solid State Drive
A solid-state drive (SSD) is a new generation of storage device used in computers. SSDs use flash-based memory, which is much faster than a traditional mechanical hard disk. Upgrading to an SSD is one of the best ways to speed up your computer. Learn how SSDs work and how to keep them optimized with a specialized
performance-boosting tool. (Avast)
o Blu-Ray
A Blu-ray disk (BD) is a high-capacity optical disk medium developed for recording, rewriting, and playing back high-definition video. Blu-ray was jointly developed by a group of personal computer and consumer electronics companies called the Blu-ray Disc Association.
o DVD (Digital Versatile Disk)
A digital versatile disc (DVD) is an optical disc storage medium like a compact disc, but with enhanced data storage capacities as well as with higher quality of video and audio formats. Codeveloped by Sony, Panasonic, Philips, and Toshiba in 1995, the DVD is widely used for video formats, audio formats as well software and computer files. (Techopedia, Digital Versatile Disc (DVD), 2017)
Characteristics of computer storage devices
o Volatility
1. Volatile — Requires constant power to maintain the stored
information. All contents are erased when the system’s power is
turned off or interrupted.
2. Non — Volatile — Will retain the stored information even if it is not constantly supplied with electric power. Non-volatile memory is the device that keeps the data even when the current is off.
o Accessibility
1. Random Access — Any location in storage can be accessed at any moment in approximately the same amount of time.
2. Sequential Access — The accessing of pieces of information will be in a serial order, one after the other; therefore, the time to access a particular piece of information depends upon which piece of information was last accessed.
o Mutability
o A computer without some amount of read/write storage for primary storage purposes would be useless for many tasks. Allows information to be overwritten at any time.
Read/Write Storage — A computer without some amount of read/write storage for primary storage purposes would be useless for many tasks. Allows information to be overwritten at any time.
Read Only Storage — Retains the information stored at the time of manufacture and write once storage (WORM) allows the information to be written only once at some point after manufacture.
Slow Write, Fast Read Storage — Read/write storage which allows information to be overwritten multiple times, but with the write operation being much slower than the read operation
o Addressability
Location-addressable — Each individually accessible unit of information in storage is selected with its numerical memory address.
File addressable — Information is divided into files of variable length, and a particular file is selected with human-readable directory and file names.
Content-addressable — It can be implemented by software (computer program) or hardware (computer device), with hardware being faster but more expensive option, and less memory per device.
References
(n.d.). Retrieved from https://www.avast.com/c-what-is-ssd
E., N. (n.d.). What is Flash Memory Technology » Electronics Notes. Retrieved from https://www.electronics-notes.com/articles/electronic_components/semiconductor-ic-memory/flash-technology-what-is.php
E.R S, B. (2021, 09 19). Magnetic Storage Devices: Examples, Types, Advantages, Disadvantages. Retrieved from DigitalThinkerHelp: https://digitalthinkerhelp.com/what-is-magnetic-storage-definition-devices-examples-and-types/
Storage Devices. (2019, 07 20). Retrieved from Computer Science GCSE GURU: https://www.computerscience.gcse.guru/theory/storage-devices#hard-disk-drive
STORAGE TECHNOLOGIES BY: SHIVENDRA GAURAV. (n.d.). Retrieved from https://slidetodoc.com/storage-technologies-by-shivendra-gaurav-hierarchy-of-storage/
Techopedia. (2013, 06 27). Offline Storage. Retrieved from Techopedia.com: https://www.techopedia.com/definition/1102/offline-storage
Techopedia. (2013, 07 01). Primary Storage Device. Retrieved from Techopedia.com: https://www.techopedia.com/definition/13097/primary-storage-device
Techopedia. (2017, 01 26). Digital Versatile Disc (DVD). Retrieved from Techopedia.com: https://www.techopedia.com/definition/32079/digital-versatile-disc-dvd
Techopedia. (2020, 08 17). Storage Device. Retrieved from Techopedia.com: https://www.techopedia.com/definition/1119/storage-device
V., S. (2020, 05 20). Top 10 Cloud Storage & File-Sharing Services for 2020. Retrieved from Cloud Academy: https://cloudacademy.com/blog/top-10-cloud-storage-file-sharing-services-for-2020/
What Is Blu-ray and How Is It Different From DVD? (2021, 09 22). Retrieved from https://www.lifewire.com/what-is-blu-ray-1846537